Covid-19 - Asymptomatic cases and incubation period

Articles 21/03/2020

by Antonino Napoleone, Giuseppe Scarlata, Domenico Gangemi | March 21, 2020

In one of the most critical moments of the history of Italy at economic, social and health levels, as Italian citizens and as European citizens, we feel obliged to contribute by sharing our studies and scientific researches with the community. Our goal is to arouse the interest and make accessible topics related to bio-medical sciences, new discoveries and technological development. We will try to be supportive through broad and comprehensive scientific communication aimed at fighting against misinformation and fake news that are spreading out harmfully.

Covid-19 – Asymptomatic cases and incubation period.

The first case of COVID-19 (Coronavirus disease – 2019) was reported by Chinese authorities to WHO on 31 December 2019 from a patient affected by viral pneumonia in Wuhan, China. On 21 March 2020, exactly one month from the first Italian case detected in Lombardia, 47,021 cases are registered in Italy, 284,566 cases worldwide distributed in 166 countries. This led the WHO to the decision on 11 March 2020 to announce the COVID-19 outbreak a pandemic. Recent large-scale studies show that 5% of cases positive for the virus develop critical symptoms, 14% develop severe symptoms, while 81% show mild symptoms. In the latter category, there is not always or not completely need to run a diagnostic test, which could mean that the number of infected people can be “n” times higher than official epidemiological data. These do not include asymptomatic and pre-symptomatic cases. Even though they do not present any significant symptoms, they represent a widespread and unsuspecting source of infection. This makes the pandemic management and containment a real challenge. Hence the WHO recommendations to increase as much as possible the identification and diagnosis of suspected cases or symptomatic contacts of confirmed cases. The incubation period is on average of 5-7 days with a maximum of 14 or even 17 days until the development of mild to severe symptoms highly influenced by factors such as gender, age, pre-existence of chronic pathological conditions (diabetes, chronic respiratory diseases, cardio-cerebrovascular diseases). The stringent containment measures adopted by the Italian government on 11 March 2020 and taken as a model in different times and ways by the other European governments aim to limit the spread of the virus, limiting contact between asymptomatic cases, pre-symptomatic cases and the categories most at risk mentioned above. Staying at home, closing schools and universities, canceling social events, cutting flights and train/bus travels, suspending the Schengen agreement, intensifying hygiene measures are all aimed at saving lives and avoiding saturating hospitals already on the verge of collapse in the most affected areas. We are the cradle of Western civilization, beauty and culture, Europe and the world will look at us and admire us when we will soon rise again. Please respect the rules together and share and have faith in medical sciences rather than the media, we all need to work together to stop all of this.